This example shows how to build surface by approximating other surface in areas. In this example 5 different areas were used. Suppose that for four of them (area1, area2, area3 and area4) we know surface values approximately, and for one of them (area6) we know them exactly. So, we want to build surface, which approximates as exactly as possible values for area6 and "not so exactly" for areas 1-4.
Here is the image of the resulting surface (red colour for areas 1-4, green colour for area6):
Pic 1. Surface built from regions of other surface
This result was obtained with "examples/surfit/curvs/area_surf.tcl" script.